1. Field of the Invention
The present invention relates to a DNC (Direct Numerical Control) system, and in particular, to improvement of a DNC system for die machining.
2. Description of the Related Art
There is a known DNC system having the structure in which a plurality of NC machine tools are connected to one host computer, and NC data is directly transmitted from the host computer to the NC machine tools. Such a system is often applied in performing a complicated diesinking operation requiring mass NC data, or other operations.
However, in the conventional DNC system, a LAN (Local Area Network) system has been directly connected between the host computer and the NC machine tools. For this reason, it is necessary for the host computer to execute all the processings such as converting different-format data (setup or housekeeping data) required for changing a setup into NC data, transmitting the converted setup data and NC data for machining, or the like. Particularly, during the complicated diesinking operation, excessive load is put on the host computer, as a consequence, there tends to be an interference in the data transmission to the NC machine tools. Further, If the NC machine tools perform part of the process to be executed by the host computer, for example, a process for converting different format data for changing the setup into NC data, load on the side of the NC machine tool increases, which causes the processing speed to drop. For this reason, sometimes there is the need of restricting the data transmission from the host computer to the NC machine tools.